lib/relocwrapper.c

   1 /* Relocating wrapper program.
   2    Copyright (C) 2003, 2005-2007, 2009-2020 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2003.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Dependencies:
  19    relocwrapper
  20     -> progname
  21     -> progreloc
  22        -> stat
  23           -> filename
  24           -> pathmax
  25           -> verify
  26        -> areadlink
  27           -> careadlinkat
  28              -> allocator
  29           -> readlink
  30              -> stat
  31        -> canonicalize-lgpl
  32           -> filename
  33           -> malloca
  34           -> lstat
  35           -> readlink
  36     -> relocatable
  37     -> setenv
  38        -> malloca
  39     -> fprintf-posix [ignore, cut dependency tree here]
  40     -> strerror [ignore, cut dependency tree here]
  41     -> c-ctype
  42
  43    Macros that need to be set while compiling this file:
  44      - ENABLE_RELOCATABLE 1
  45      - INSTALLPREFIX the base installation directory
  46      - INSTALLDIR the directory into which this program is installed
  47      - LIBPATHVAR the platform dependent runtime library path variable
  48      - LIBDIRS a comma-terminated list of strings representing the list of
  49        directories that contain the libraries at installation time
  50
  51    We don't want to internationalize this wrapper because then it would
  52    depend on libintl and therefore need relocation itself.  So use only
  53    libc functions, no gettext(), no error(), no xmalloc(), no xsetenv().
  54  */
  55
  56 #define _GL_USE_STDLIB_ALLOC 1
  57 #include <config.h>
  58
  59 #include <stdio.h>
  60 #include <stdlib.h>
  61 #include <string.h>
  62 #include <unistd.h>
  63 #include <errno.h>
  64
  65 #include "progname.h"
  66 #include "relocatable.h"
  67 #include "c-ctype.h"
  68 #include "verify.h"
  69
  70 /* Use the system functions, not the gnulib overrides in this file.  */
  71 #undef fprintf
  72 #undef strerror
  73
  74 /* Return a copy of the filename, with an extra ".bin" at the end.
  75    More generally, it replaces "${EXEEXT}" at the end with ".bin${EXEEXT}".  */
  76 static char *
  77 add_dotbin (const char *filename)
  78 {
  79   size_t filename_len = strlen (filename);
  80   char *result = (char *) malloc (filename_len + 4 + 1);
  81
  82   if (result != NULL)
  83     {
  84       if (sizeof (EXEEXT) > sizeof (""))
  85         {
  86           /* EXEEXT handling.  */
  87           const size_t exeext_len = sizeof (EXEEXT) - sizeof ("");
  88           static const char exeext[] = EXEEXT;
  89           if (filename_len > exeext_len)
  90             {
  91               /* Compare using an inlined copy of c_strncasecmp(), because
  92                  the filenames may have undergone a case conversion since
  93                  they were packaged.  In other words, EXEEXT may be ".exe"
  94                  on one system and ".EXE" on another.  */
  95               const char *s1 = filename + filename_len - exeext_len;
  96               const char *s2 = exeext;
  97               for (; *s1 != '\0'; s1++, s2++)
  98                 {
  99                   unsigned char c1 = *s1;
 100                   unsigned char c2 = *s2;
 101                   if (c_tolower (c1) != c_tolower (c2))
 102                     goto simple_append;
 103                 }
 104               /* Insert ".bin" before EXEEXT or its equivalent.  */
 105               memcpy (result, filename, filename_len - exeext_len);
 106               memcpy (result + filename_len - exeext_len, ".bin", 4);
 107               memcpy (result + filename_len - exeext_len + 4,
 108                       filename + filename_len - exeext_len,
 109                       exeext_len + 1);
 110               return result;
 111             }
 112         }
 113      simple_append:
 114       /* Simply append ".bin".  */
 115       memcpy (result, filename, filename_len);
 116       memcpy (result + filename_len, ".bin", 4 + 1);
 117       return result;
 118     }
 119   else
 120     {
 121       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 122       exit (1);
 123     }
 124 }
 125
 126 /* List of directories that contain the libraries.  */
 127 static const char *libdirs[] = { LIBDIRS NULL };
 128 /* Verify that at least one directory is given.  */
 129 verify (sizeof (libdirs) / sizeof (libdirs[0]) > 1);
 130
 131 /* Relocate the list of directories that contain the libraries.  */
 132 static void
 133 relocate_libdirs ()
 134 {
 135   size_t i;
 136
 137   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 138     libdirs[i] = relocate (libdirs[i]);
 139 }
 140
 141 /* Activate the list of directories in the LIBPATHVAR.  */
 142 static void
 143 activate_libdirs ()
 144 {
 145   const char *old_value;
 146   size_t total;
 147   size_t i;
 148   char *value;
 149   char *p;
 150
 151   old_value = getenv (LIBPATHVAR);
 152   if (old_value == NULL)
 153     old_value = "";
 154
 155   total = 0;
 156   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 157     total += strlen (libdirs[i]) + 1;
 158   total += strlen (old_value) + 1;
 159
 160   value = (char *) malloc (total);
 161   if (value == NULL)
 162     {
 163       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 164       exit (1);
 165     }
 166   p = value;
 167   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 168     {
 169       size_t len = strlen (libdirs[i]);
 170       memcpy (p, libdirs[i], len);
 171       p += len;
 172       *p++ = ':';
 173     }
 174   if (old_value[0] != '\0')
 175     strcpy (p, old_value);
 176   else
 177     p[-1] = '\0';
 178
 179   if (setenv (LIBPATHVAR, value, 1) < 0)
 180     {
 181       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 182       exit (1);
 183     }
 184 }
 185
 186 int
 187 main (int argc, char *argv[])
 188 {
 189   char *full_program_name;
 190
 191   /* Set the program name and perform preparations for
 192      get_full_program_name() and relocate().  */
 193   set_program_name_and_installdir (argv[0], INSTALLPREFIX, INSTALLDIR);
 194
 195   /* Get the full program path.  (Important if accessed through a symlink.)  */
 196   full_program_name = get_full_program_name ();
 197   if (full_program_name == NULL)
 198     full_program_name = argv[0];
 199
 200   /* Invoke the real program, with suffix ".bin".  */
 201   argv[0] = add_dotbin (full_program_name);
 202   relocate_libdirs ();
 203   activate_libdirs ();
 204   execv (argv[0], argv);
 205   fprintf (stderr, "%s: could not execute %s: %s\n",
 206            program_name, argv[0], strerror (errno));
 207   exit (127);
 208 }